1. Field of the Invention
The present teachings generally relate to rectilinear measuring systems and articulated arm coordinate measuring machines and more particularly to a system and methods for transprojecting geometry data.
2. Description of the Related Art
Rectilinear measuring systems, also referred to as coordinate measuring machines (CMM's) and articulated arm measuring machines including portable coordinate measuring machines (PCMM's) have been described for generating geometry information from various objects and areas. In general, these devices capture the structural characteristics of an object for use in electronic rendering and duplication. One example of a conventional apparatus used for coordinate data acquisition comprises a support and a moveable arm made up of hinged segments to which a contact-sensitive probe or remote scanning device is attached. Geometry information or three-dimensional coordinate data characterizing the shape, features, and size of the object may be acquired by tracing or scanning along the object's surface and contours. Probe or scanning device movement is typically tracked relative to a reference coordinate system resulting in a collection of data points and information that may be used to develop an accurate electronic rendering of the object. In conventional implementations, the acquired geometry information is processed by a computer capable of making use of the information to model the surface contours and dimensions of the object.
One limitation found in many conventional instruments is that they are generally intended to operate in an environment wherein geometry information captured by the probe or remote scanning device forms an electronic representation of the object without the benefit of photographic dimensional details scaled to the same coordinate system as the geometry information. Providing the ability to evaluate and analyze object coordinate measurements overlaid upon appropriate views and perspectives of a photographic representation of the object provides numerous advantages over conventional rendering approaches. In particular, visual rendering in this manner aids in giving context, dimension, and realism to the geometry information, as well as, providing a convenient means for review and validation.
Systems have been described which provide a limited coupled optical and mechanical object acquisition environment including, for example, U.S. Pat. Nos. 4,908,951 and 5,615,489. These apparatuses are generally directed towards systems for remotely monitoring a probe contact region and surrounding area in a two dimensional context and fail to adequately provide the ability to superimpose or transproject scaled 3D geometry or coordinate data upon 2D images that can be made to accurately reflect the various object details in different orientations and rotations. Coordinate transprojection in such a manner may add significantly to the functionality and potential utility of coordinate acquisition devices contributing to improved design, engineering, and analysis capabilities.
However desirable, accurate coupling of digital object image information to coordinate data presents a number of difficulties in order to capture the characteristics and benefits of each in combination. In particular, calibration of the measuring environment both from the perspective of an object image acquisition device (providing two-dimensional data) as well as from the perspective of the coordinate acquisition probe or remote scanning device (providing three-dimensional data) using a singular coordinate system is generally necessary to allow presentation of both types of information in an integrated manner. Furthermore, it may be desirable to implement a perspective switching or image panning functionality in conjunction with the display system while preserving coordinate scaling accuracy. In these and other regards, conventional instruments and methods fail to adequately provide flexible transprojection capabilities to model 3D coordinate data in combination with 2D photographic images.
From the forgoing it will be appreciated that there is a need for an object image transprojection system that is capable of not only providing object monitoring capabilities but also a means by which digital images captured from the object can be accurately overlaid with scaled coordinate or geometry information. Furthermore, there is a need for a system which allows this data to be rapidly visualized while preserving the accuracy and precision of the measurements.